1. Field of the Invention
This invention relates to vapor-compression evaporative cooling systems that use water as a refrigerant in an open system, and in particular, to vapor-compression evaporative cooling systems capable of processing large volumetric flow rates of water vapor and removing noncondensibles from the system and to methods using such systems. This invention also relates to low-friction, positive-displacement compressors useful in such cooling systems and to means for removing noncondensibles from such cooling systems.
2. Description of the Background
Conventional vapor-compression air conditioning systems employ a working fluid such as chlorofluorocarbons (CFCs). Liquid CFC is introduced into a low-pressure heat exchanger where it absorbs heat at a low temperature and vaporizes. A compressor repressurizes the vapors that are introduced to a high-pressure heat exchanger where heat is rejected to the environment and the vapors condense. The condensate is reintroduced into the low-pressure heat exchanger, thus completing the cycle.
The use of CFCs raises two important environmental concerns. First, CFCs are stable enough to enter the stratosphere where they decompose to chlorine free radicals that catalyze the destruction of ozone. This is unfortunate because ozone absorbs ultraviolet radiation which damages DNA in plants and animals. Second, CFCs absorb infrared radiation which contributes to global warming.
Because CFCs cannot be released into the environment, they must be contained within the air conditioning system. The evaporator and condenser heat exchangers have a sizable temperature difference between the ambient environment and the working fluid (about 10 to 15xc2x0 C.) which greatly reduces the Carnot efficiency. Further limiting the efficiency is the fact that the condenser rejects heat at the dry-bulb temperature. The wet-bulb temperature is generally about 5-30xc2x0 C. less than the dry-bulb temperature. Thus, if heat were rejected at the wet-bulb temperature, the Carnot efficiency could be improved even more.
In addition, compressors used in conventional systems typically have compressing components that are in direct contact with each other. The close fit between components has heretofore been necessary to prevent blow-by of high-pressure compressed vapors. However, the friction resulting from the close contact between components reduces efficiency, creates heat and causes wear on the components.
Although the use of water in place of CFCs as the air-conditioning working fluid has been considered, proposed systems have been generally unworkable because the vapor density is very low requiring large volumes of water vapor to be compressed.
One study by the Thermal Storage Applications Research Center of the University of Wisconsin, The Use of Water as a Refrigerant, Report No. TSARC 92-1, March 1992, studied the use of water as a refrigerant. This study concluded that for water-based air conditioning, positive displacement compressors are not suitable for use in such systems. Rather, only dynamic compressors are suitable.
Although xe2x80x9cswamp coolerxe2x80x9d air conditioners are employed in arid regions of the United States that have low wet-bulb temperatures, they have limited usefulness. In swamp coolers, ambient air is contacted with water which evaporates and cools the air. No external power is required other than for air-handling blowers. Unfortunately, these simple devices are restricted to regions of low humidity (e.g., Arizona, New Mexico) and are not suitable for many regions of the world. Further, although the air is cooler, it has increased humidity which can make the air feel xe2x80x9cclammy.xe2x80x9d
There is therefore a need for an environmentally friendly, efficient and economical means for air conditioning in all types of climates. The present invention overcomes the above noted deficiencies in the art by providing air conditioning systems that use water as the working fluid rather than CFCs, thus eliminating potential CFC emissions. These systems are not limited to regions of low humidity. The present invention is directed to cooling systems that are 1.7 to 3.9 times more efficient than conventional air conditioning systems and that have manufacturing costs less than, or competitive with, conventional air conditioning systems.
In addition, unlike the teachings of the literature, it has been discovered that high-volume, low-pressure positive displacement compressors can be utilized in cooling systems that use water as the working fluid. It has further been discovered that because of the relatively low pressures (i.e., 0.2-0.7 psia) in the compressors of the cooling systems of the present invention, the gaps between the compressing components can be comparatively large, and that such large gaps are not only acceptable, but actually can be beneficial from both an efficiency and wear standpoint. Because of the low friction, the novel compressors can be scaled up to the necessary size. For example, such a gap-containing, positive displacement compressor can process the 1400 ft3/min of low-pressure water vapor needed to produce 3 tons of cooling.
In addition, it has been discovered that water, with or without suitable wicking material, cat be used to fill the gaps between the components, and thereby create an effective, but low-friction seal between the compressing components. Thus, the present invention is also directed to novel positive displacement compressors which are useful in air conditioning systems using water as the working fluid. These compressors include novel compressors which are useful in the disclosed systems as well as in other applications. The present invention is also directed to novel pumps useful for removing noncondensibles from the disclosed cooling systems as well as in other applications. Finally, the present invention is directed to novel seals and mounting apparatus useful in the disclosed compressors.
In accordance with one embodiment of the present invention, a vapor-compression evaporative air conditioning system is provided that comprises: an evaporator; a room air contactor for directly exchanging heat between room air and a quantity of water from the evaporator; means for compressing a volume of water vapor, thereby creating a vacuum on the water in the evaporator, the means for compressing comprising a positive displacement compressor, the compressor comprising an inlet and an outlet, wherein low-pressure water vapors from the evaporator enter the inlet and compressed water vapors exit the outlet; a condenser for receiving the compressed water vapors; means for reducing a water content of the vapors exiting the condenser; means for removing noncondensibles from the condenser, and an ambient air contactor for directly exchanging heat between the ambient air and water from the condenser. The positive displacement compressor is preferably a low-friction compressor comprising at least two compressing components, which do not substantially contact one another. The advantages of this system include that it is an efficient low-friction system capable of functioning in humid environments.
The compressing components may comprise an inner gerotor, an outer gerotor and a housing; an orbiting (or mobile) scroll, a stationary (or fixed) scroll and a housing; a housing and a piston a housing, a rotor, and a flap; an inner drum, an outer drum and a swinging vane; or a housing, a rotor and a sliding vane. In a preferred embodiment there is a gap between at least two of the compressing components. Water or water and a wick may be used as a sealant in the gap.
In one embodiment of this system, the means for compressing water vapor comprises a gerotor compressor comprising an inner gerotor and an outer gerotor, the inner gerotor disposed within the outer gerotor, each gerotor comprising a plurality of teeth. The inner gerotor has one less tooth than the outer gerotor, thereby creating a void volume between the inner gerotor and the outer gerotor. An inlet port and a discharge port communicate with the void volume. The discharge port may have a variable port mechanism that changes the position of a leading edge of the discharge port. This variable port mechanism may be positioned using electrically actuated means controlled by a thermocouple signal.
The variable port mechanism may comprise an electrically controlled servo motor, the motor rotating a threaded rod, a bellows, and a non-rotating nut coupled to the bellows, the rod axially positioning the non-rotating nut. Alternatively, the variable port mechanism may comprise a plurality of plates disposed adjacent to the discharge port and means for sequentially moving the plates to vary the leading edge of the discharge port. The variable port mechanism may be positioned using a bellows, actuated by a bulb containing a liquid, wherein the liquid in the bulb has a vapor pressure proportional to the condenser temperature which acts on the bellows.
The gerotor compressor may further comprise an electric motor for driving the gerotor compressor, a first pump for pumping cooled water from the evaporator to a packing in the room air contactor, a filter disposed between the room air contactor and the evaporator, wherein water from the room air contactor flows through the filter to the evaporator, a second pump for pumping water from the condenser to a packing in the ambient air contactor, and a fan for driving ambient air countercurrently against the packing.
Because of the low action between when compressing components of the compressors of the present invention, the compressors of the present invention use novel actuation means to actuate the gerotors.
For instance, one embodiment uses a low-friction gerotor compressor in which a first drive shaft drives the outer gerotor, and the actuation means comprises an internal gearbox containing a plurality of spur gears, the plurality being an odd number. One of the spur gears is coupled to the first drive shaft and another of the spur gears is coupled to a second drive shaft, the second drive shaft being offset from the first drive shaft, thereby suspending the gearbox between the first drive shaft and the second drive shaft. The first drive shaft is coupled to the outer gerotor through a plate that comprises a plurality of prongs in contact with a plurality of holes in the outer gerotor. The second drive shaft is coupled to the inner gerotor.
In another embodiment, a different novel actuated gerotor compressor is used. In this compressor, a first shaft drives the outer gerotor and the actuation means comprises a spur gear set comprised of a large gear coupled to the outer gerotor, the large gear containing a plurality of teeth on an inside diameter, and a small gear coupled to the inner gerotor, the small gear containing a plurality of teeth on an outside diameter, the large gear meshing with the small gear, and further comprised of a second shaft about which the inner gerotor spins, wherein the second shaft contains a crook establishing an offset between the first shaft and the second shaft. Preferably, for cooling and lubrication purposes, the gears are immersed in liquid water. A gear set may be attached to a bottom portion of the inner gerotor allowing for power take off.
In an alternative embodiment using still another novel actuated gerotor compressor, the actuation moans may comprise a plurality of rollers attached to the inner gerotor, wherein the rollers extend beyond a plurality of walls of the inner gerotor and are in contact with the outer gerotor, and wherein the outer gerotor drives the inner gerotor through the rollers. In this embodiment, the inner gerotor may be mounted on a rotating shaft and the rotating shaft extends outside of the compressor housing.
In still another embodiment using a novel actuated gerotor compressor, the actuation means comprises a large gear coupled to the outer gerotor, the large gear comprising a plurality of teeth on an inside diameter, a small gear coupled to the inner gerotor, the small gear comprising a plurality of teeth on an outside diameter, the large gear meshing with the small gear, and a stationary central shaft, wherein the stationary central shaft contains two crooks that create an offset between an axis of the inner gerotor and an axis of the outer gerotor, and wherein the stationary shaft comprises a first end and a second end, the first end of the stationary shaft affixed to a first perforated housing end plate through a pivotable mount that prevents rotation of the stationary shaft and the second end of the stationary shaft located in a rotating bearing cup coupled to the outer gerotor. In this embodiment, the gerotor compressor may further comprise a second perforated housing plate, a first perforated rotating plate and a second perforated rotating plate, such that both the rotating plates are connected to the outer gerotor, and a first stationary plate and a second stationary plate adjacent to both gerotors, the first stationary plate containing an inlet port and the second stationary plate containing a discharge port. Alternatively, the inlet and outlet port can be placed in one of the plates. Preferably, the gears are immersed in liquid water to provide cooling and lubrication.
In the novel air conditioning system disclosed herein, the system may further comprise means for inhibiting microorganisms in the water in the room air contactor, such as an ozone generator or UV radiation. In addition, the means for removing noncondensibles may comprise an aspirator or a vacuum pump, such as the novel pumps disclosed below.
In other embodiments of the disclosed system, the compressor means may comprise a novel low-friction scroll compressor.
In yet another embodiment of the disclosed system, the compressor means comprises a novel actuated flap compressor. This compressor comprises: a compressor housing, the housing having an interior wall, an inlet, and an outlet; a rotor disposed in the housing; a flap, the flap having a first end and a second end, the first end being coupled to the rotor and the second end being propelled in an outward direction during rotation of the rotor; and means for preventing the second end of the flap from touching the interior wall of the housing.
In still another embodiment, the compressor means comprises a novel multi-vane actuated flap compressor. This compressor preferably comprises: an outer drum having an axis; an inner drum rotatably disposed in the outer drum; a plurality of vanes, each vane having a first end and a second end opposite the first end, the vanes pivotally attached to the inner drum at the first end and having a vane tip at the second end, the vane tips being propelled radially outward during rotation of the inner drum; a connecting rod coupled to each vane tip, the rods maintaining a gap between the vane tips and the outer drum; and coupling means for causing the connecting rods to rotate about the axis of the outer drum.
Alternatively, the compressor means may be a novel low-friction reciprocating compressor comprising: a compressor housing; an oscillating center shaft disposed partly within the housing, the shaft comprising a top end and a bottom end, the top end comprising a protrusion which rides in a sinusoidal groove in a rotating cam driven by a motor; and at least one plate disposed in the housing and attached to the shaft and oscillating therewith, the at least one plate having a groove through which water flows to make a seal between the compressor housing and the plates. In one embodiment of the reciprocating compressor, the cam contains a plurality of sinusoidal grooves.
In the novel air conditioning systems disclosed herein, the components may be disposed in three concentric chambers. In one such embodiment the ambient air contactor is disposed in an outermost chamber of the concentric chambers, the compressor means and the evaporator are disposed in an innermost chamber of the concentric chambers, and the condenser is disposed in a middle concentric chamber. In another system, comprising two concentric chambers, the ambient air contactor is disposed in an outermost chamber of the concentric chambers, and the compressor means, the evaporator and the condenser are disposed in an innermost concentric chamber.
The novel systems disclosed herein may further comprise means for providing makeup water to the evaporator and condenser, which is preferably accomplished using one or more float valves. In addition, the room air contactor may comprise a spray tower to place water from the evaporator in direct contact with the room air. The room air contactor may comprise a packing, such that the water from the evaporator passes over the packing, and the room air passes through the packing. The packing preferably comprises corrugated chlorinated polyvinyl chloride. In the disclosed embodiments, the condenser may be a spray condenser, jet condenser, or may comprise a packing.
The present invention is also directed to a novel method for cooling air comprising the steps of: compressing a large volume of low-pressure water vapor with a compressor, thereby creating a vacuum on a quantity of water in an evaporator and causing evaporation and the water to be cooled; pumping cooled water from the evaporator and contacting the cooled water countercurrently with room air in a room air contactor, thereby cooling room air; routing water from the room air contactor to the evaporator, causing the water to flash and cool; sending compressed water vapors exiting the compressor to a condenser for condensation; countercurrently directly contacting the water vapors exiting the condenser with a stream of chilled water from the evaporator to reduce the water content from air; removing noncondensibles from the condenser; routing liquid water from the condenser to an ambient air contactor, where ambient air is contacted countercurrently with liquid water pumped from the condenser; providing make-up water to replace evaporated water; and draining salt water.
Preferably, the compressor is a positive displacement compressor. More preferably, the compressor is a low-friction positive displacement compressor comprising at least two compressing components, in which the compressing components do not substantially contact each other, i.e., although some contact can occur without departing from the spirit and scope of the invention, generally there are clearance gaps, which preferably may be a few thousandths of an inch, between components. The method may further comprise the step of spraying water into the compressor to prevent temperature increase during the compression stage.
In one embodiment of the method, water from the room air contactor may flow countercurrently through a plurality of evaporators. Alternately, condensation may occur in multiple stages. In still another embodiment of the invention, both evaporation and condensation take place in multiple stages. Noncondensibles may be removed by one or a plurality of compressors.
The present invention is also directed to novel methods of cooling air using multistage systems. One such method comprises the steps of: compressing a large volume of low-pressure water vapor in a plurality of compressor stages, thereby creating a vacuum on a quantity of water in a plurality of evaporators and causing the water to be cooled; pumping cooled water from the evaporators and contacting the cooled water countercurrently with room air in a room air contactor, thereby cooling room air; routing water from the room air contactor to the evaporators, causing the water to flash and cool; sending compressed water vapors exiting the last compressor stage to a condenser for condensation; countercurrently directly contacting the water vapors exiting the condenser with a stream of chilled water from at least one of the evaporators to reduce the water content from air; removing noncondensibles from the condenser; routing liquid from the condenser to an ambient air contactor, wherein ambient air is contacted countercurrently with liquid water pumped from the condenser; providing make-up water to replace evaporated water; and draining salt water. Condensation may take place in a single stage or in multiple stages. The compressor stages preferably comprise one or more positive displacement compressors or one or more dynamic compressors. However, in the multistage systems disclosed herein, the compressor stages may be either positive displacement compressors, or dynamic compressors, or a mixture of each.
The present invention is also directed to novel low-friction positive displacement compressors useful in the cooling systems of the present invention as well as in other applications. They have the advantage of low friction and high efficiency. These compressors comprise at least two compressing components, such that the compressing components do not substantially contact one another. The compressing components may comprise: an inner gerotor, an outer gerotor and a housing; an orbiting scroll, a stationary scroll and a housing; a housing and a piston; a housing, a rotor and a sliding vane; a housing, a rotor and a flap; or an inner drum, an outer drum and a swinging vane, and there is a gap between at least two of the compressing components. Water, or water and a wick may be used as a sealant in the gap.
One such novel compressor comprises a gerotor compressor comprising an inner gerotor and an outer gerotor, the inner gerotor disposed within the outer gerotor, each gerotor comprising a plurality of teeth. The inner gerotor has one less tooth than the outer gerotor, thereby creating a void volume between the inner gerotor and the outer gerotor. In addition, there is a gap between the inner gerotor and outer gerotor. The gerotor compressor further comprises an inlet port and a discharge port; the ports communicate with the void volume.
The discharge port may have a variable port mechanism that changes the position of a leading edge of the discharge port. In one embodiment, the variable port mechanism comprises an electrically controlled servo motor, the motor rotating a threaded rod, a bellows, and a non-rotating nut coupled to the bellows, the rod axially positioning the non-rotating nut. The variable port mechanism may be positioned using electrically actuated means. In another embodiment, it may be positioned using a bellows, the bellows being actuated by a bulb containing a liquid, the liquid ill the bulb having a vapor pressure proportional to the condenser temperature which acts on the bellows. In yet another embodiment, the variable port mechanism comprises a plurality of plates disposed adjacent to the discharge port and means for sequentially moving the plates to vary the leading edge of the discharge port.
The present invention is also directed to novel low-friction gerotor compressors which use actuation means to actuate the gerotors allowing for reduced friction. In one such embodiment, a first drive shaft drives the outer gerotor and the actuation means comprises an internal gearbox containing a plurality of spur gears, the plurality being an odd number, and wherein one of the spur gears is coupled to the first drive shaft and another of the spur gears is coupled to a second drive shaft, the second drive shaft being offset from the first drive shaft thereby suspending the gearbox between the first drive shaft and the second drive shaft, and the first drive shaft is coupled to the outer gerotor tough a plate that comprises a plurality of prongs in contact with a plurality of holes in the outer gerotor. A second drive shaft is coupled to the inner gerotor.
In another novel actuated gerotor compressor, a first drive shaft drives the outer gerotor and the actuation means comprises a spur gear set comprised of a large gear coupled to the outer gerotor, the large gear containing a plurality of teeth on an inside diameter, and a small gear coupled to the inner gerotor, the small gear containing a plurality of teeth on an outside diameter. In this embodiment the large gear meshes with the small gear, and there is a second shaft about which the inner gerotor spins. This second shaft contains a crook establishing an offset between the first shaft and the second shaft.
In another embodiment of a novel actuate a gerotor compressor, the actuation means comprises a plurality of rollers attached to the inner gerotor, wherein the rollers extend beyond a plurality of walls of the inner gerotor and are in contact with the outer gerotor, and the outer gerotor drives the inner gerotor through the rollers.
In another embodiment, the inner gerotor and outer gerotor are disposed in a housing, a first drive shaft drives the outer gerotor, and the actuation means comprises a spur gear set comprised of a large gear, coupled to the outer gerotor, the large gear containing a plurality of teeth on an inside diameter, and a small gear coupled to the inner gerotor, the small gear containing a plurality of teeth on an outside diameter. In this embodiment, the large gear meshes with the small gear, and there is a second shaft attached to the inner gerotor which spins on a bearing means, such as bearings affixed to the housing.
In still another embodiment, a first drive shaft drives the inner gerotors, and the actuation means comprises a spur gear set comprised of a large gear coupled to the outer gerotor, the large gear containing a plurality of teeth on an inside diameter, and a small gear coupled to the inner gerotor, the small gear containing a plurality of teeth on an outside diameter, wherein the large gear meshes with the small gear, and further comprises a second nonrotating shaft about which the outer gerotor spins, wherein the second shaft contains a crook establishing an offset between the first and the second shafts.
In still another embodiment, the actuation means comprises a large gear coupled to the outer gerotor, the large gear comprising a plurality of teeth on an inside diameter, a small gear coupled to the inner gerotor, the small gear comprising a plurality of teeth on an outside diameter, the large gear meshing with the small gear, and a stationary central shaft, wherein the stationary central shaft contains two crooks that create an offset between an axis of the inner gerotor and an axis of the outer gerotor, and wherein the stationary shaft comprises a first end and a second end, the first end of the stationary shaft affixed to a first perforated housing end plate through a pivotable mount that prevents rotation of the stationary shaft and the second end of the stationary shaft located in a rotating bearing cup coupled to the outer gerotor. Preferably, the pivotable mount prevents the stationary central shaft from rotating, but allows for angular and axial variation.
In this embodiment, the pivotable mount may comprise a ring, spokes and a hub, which are coupled to the shaft. The ring has a spherical outer diameter which is disposed within an inlet of the first perforated housing end plate. In addition, the gerotor compressor may further comprise a second perforated housing plate, a first perforated rotating plate and a second perforated rotating plate, wherein both the rotating plates are connected to the outer gerotor, and a first stationary plate and a second stationary plate which are adjacent to the inner and outer gerotors, the first stationary plate containing an inlet port and the second stationary plate containing a discharge port.
The present invention is also directed to novel low-friction scroll compressors. One such compressor comprises a stationary scroll having flutes and an orbiting scroll having flutes, the orbiting scroll orbiting around the stationary scroll. The flutes of the scrolls are separated by a gap.
The scroll compressor of the present invention may have novel means for creating orbiting motion. This compressor comprises a stationary scroll, an orbiting scroll, and means for causing the orbiting scroll to orbit around the stationary scroll, the means comprising a first gear affixed to the stationary scroll, an orbiting arm affixed to the first gear, a second intermediary gear attached to the orbiting arm, and a third gear attached to the orbiting scroll, wherein the second intermediary gear drives the third gear.
Still other embodiments of the invention are directed to novel sliding vane compressors which comprise a rotor, a sliding vane and a housing, and means for reducing friction between the vane, the rotor and the housing. In one such embodiment, the compressor comprises: a compressor housing, the housing having an interior wall, an inlet, and an outlet; a rotor disposed in the housing; a flap, the flap having a first end and a second end, the first end being coupled to the rotor and the second end being propelled in an outward direction during rotation of the rotor; and means for preventing the second end of the flap from touching the interior wall of the housing.
In still another embodiment, a novel multi-vane compressor comprises: an outer drum having an axis; an inner drum rotatably disposed in the outer drum; a plurality of vanes, each vane having a first end and a second end opposite the first end, the vanes pivotably attached to the inner drum at the first end and having a vane top at the second end, the vane tips being propelled radially outward during rotation of the inner drum; a connecting rod coupled to each vane tip, the rods maintaining a gap between the vane tips and the outer drum and coupling means for causing the connecting rods to rotate about the axis of the outer drum. In this embodiment, the inner drum is preferably rotatably driven by a first shaft, and the coupling mean comprises an offset shaft to which the connecting rod is coupled, the offset shaft being coaxial with the axis of the outer drum; and a torque coupler for transmitting rotational force to the offset shaft. Preferably, water is used as a sealant in the gaps.
Still another embodiment is directed to a novel low-friction reciprocating compressor, comprising: a compressor housing, an oscillating center shaft disposed partly within the housing, the shaft comprising a top end and a bottom end; and at least one plate disposed in the housing and attached to the shaft and oscillating therewith, the at least one plate having a groove through which water flows to make a seal between the compressor housing and the plates. In a preferred embodiment, the top end of the shaft has a protrusion which rides in a sinusoidal groove in a rotating cam driven by a motor. Alternately, the cam may contain a plurality of sinusoidal grooves.
The present invention is also directed to novel pumps useful in removing noncondensibles. Possible methods for purging noncondensibles include: 1) periodically flooding the condenser with liquid water to push out accumulated noncondensibles, 2) employing an aspirator in which the vacuum at the throat of the venturi draws out noncondensibles, and 3) employing a mechanical vacuum pump. One such embodiment comprises a vacuum pump which comprises a cylinder, a piston disposed in the cylinder, an inlet valve disposed in the cylinder, a sprayer that draws water into the cylinder, and a vent disposed in the cylinder for discharging noncondensibles and excess water. The vacuum pump is driven by a gear mounted on a main drive shaft, the gear connected to a plurality of reduction gears, wherein a first cam surface and a second cam surface are mounted on one of the reduction gears, a first roller rides on the first cam surface and a second roller rides on the second cam surface, and the first roller drives the piston and the second roller drives the inlet valve.
Another novel vacuum pump comprises a cylinder, piston disposed in the cylinder, a crank, a check valve disposed in the cylinder, and means for spraying water into the cylinder of the vacuum pump, wherein the piston is driven by the crank in a first and a second direction opposite the first direction, the piston comprising a first end, a second end, a plurality of notches, a plurality of perforations extending from the first end to the second end, and a flexible flap attached to the second end of the piston and covering one or more of the perforations, wherein the flap opens when the piston moves in the first direction and closes when the piston moves in the second direction.
Still another novel vacuum pump comprises: a first column and a second column, the columns being partially filled with liquid and having a vapor space; means for causing the liquid to oscillate in the columns; inlet means for allowing uncompressed gas to enter each of the columns; outlet means for discharging compressed gas from each of the columns; and means for spraying a fine mist of liquid into the vapor space of the first and the second columns. Preferably, the means for causing oscillation comprise a chamber connecting the first and the second columns and a reciprocating piston disposed in the chamber. The outlet means for each column preferably comprises a check valve. This oscillating pump has the ability to isothermally compress a mixture of noncondensible and condensible gases to a very high compression ratio.
Another novel vacuum pump is a gerotor vacuum pump comprising an outer gerotor and a center gerotor disposed within the outer gerotor, wherein the center gerotor is mounted on a main drive shaft and the outer gerotor is positioned by a plurality of guide rollers. Alternatively, the center gerotor is mounted on a main drive shaft and the outer gerotor is mounted within a single ball bearing.
The volumetric load on the aspirator or vacuum pump can be greatly reduced by condensing most of the water and increasing the partial pressure of the noncondensibles. The present invention employs a novel method for removing water vapor from noncondensibles in a stream of air and water vapor comprising passing the stream through a packed column with chilled water flowing countercurrently. Preferably, the packed column comprises structured packing (e.g., corrugated polyvinyl chloride) or dumped packing (e.g., ceramic saddles).
Still another embodiment is directed to a novel pivotable mounting apparatus for mounting a stationary shaft to a housing, which prevents rotation of the shaft, but allows for angular and axial variation. This apparatus comprises a ring, spokes and hub, coupled to the shaft. The ring has a spherical outer diameter, which is disposed within a cylindrical shaped opening in the housing.
Still another embodiment is directed to a novel low-friction rotary shaft seal comprising: a journal for receiving a rotary shaft, the journal configured to create a gap between the shaft and the journal, the journal further comprising a journal face; means for supplying water to the gap; and a bellows seal, the seal resting on the journal face when the shaft is stationary and lifting off the face when the shaft rotates.